CHANGES TO BUILDING REGS

From 15 June 2022 there will be significant changes to the requirements for doors and windows. Edward Stobart, head of projects at Idsystems, sheds some light on what it means for you and your project

The latest changes to Building Regulations in England and Wales for doors and windows are some of the most significant in a generation and are likely to have a long-term impact not only on the products available, but also on the design of extensions and new-build homes.

The changes that impact door and window design fall into two parts — Approved Document L: Conservation of fuel and power, which covers thermal efficiency performance standards; and the new Approved Document O: Overheating mitigation.

The updated standards within Approved Document L were announced by the government just before Christmas 2021 and take effect on 15 June 2022 with a one-year period of grace for those who have submitted a building notice, initial notice or full plans application by the first date.

With rapid increases in energy prices and the government targets for carbon emissions, thermal efficiency standards have been under the spotlight this year more than ever before and the changes to Approved Document L are just the start of the process towards achieving the Future Homes Standard by 2025. The Future Homes Standard will require new-build homes to be futureproofed with low carbon heating and world-leading levels of energy efficiency and will likely see the standards required under Approved Document L tightened even further. Under previous Building Regulations the performance required for glazed doors for extensions and renovations was a U value of 1.8W/M²K; this has reduced to 1.4W/M²K under the new standards.

As with any tightening of standards this will impact on the suitability of some of the products available and it may mean those undertaking projects are required to change their choice of door system to achieve the new performance figures required.

Whereas the changes to Part L of the Regulations are an update on existing standards, Approved Document O, which covers overheating mitigation, is a brand-new standard.

For the first time, the Regulations require homeowners to make reasonable provision to limit unwanted heat from the sun (solar gain) during summer months. The calculations extend upon the Standard Assessment Procedure (SAP) Appendix P calculations at the design stage of the project and are individual to each property and its orientation and location.

The Regulations tighten the restrictions on the proportion of glazing ( based on floor area and room orientation) and also highlight areas of the country (parts of urban and suburban London and central Manchester) identified as being high-risk areas. The likely impact of the new regulations will be a reduction in the size of glazing that can be achieved, particularly on southfacing elevations. In the short term the focus will be on glass specifications, including solar-control coatings, to reduce the solar gain (G-value) but in the longer term it will also likely see changes to the designs of projects to incorporate overhangs, brise soleil or recesses to reduce the direct sunlight into rooms when the sun is at its highest (and hottest) during summer months.